Penny Lyons: Alan for her was like her knight in shining armor. I mean, he came into her life and said, "I want to care for you. I want to care about you. And your joy is my goal."

And 59-year-old Alan Helmick wasn't just the knight in armor to Miriam. A lot of people in his hometown of Delta, Colo., felt the same way about him. Alan, the broker on Main Street, had helped people get into their homes and helped build their businesses.

Alan Helmick: My father was probably one of the best people I've ever met in my life. And I don't just say that because I'm his son.

To Alan Helmick, Jr., his father was the epitome of the All-American success story. Forty-years before his life criss-crossed with Miriam's, he was a golden-eared musician and star baseball pitcher, who married his high school sweetheart, Sharon. Together, they raised four children while Alan ran the local savings and loan, and eventually his own mortgage and title companies.

DennisMurphy: I almost think of the George Bailey character in “It's a Wonderful Life.” Come into the savings and loan and "what if I hadn't lived?" (laughter)

Alan Helmick: Right. Except my dad would have got a second job to make up the money he lost. (laughter)

But on New Year's Eve 2003, the wonderful life of Alan Helmick suddenly fell apart when Sharon died of a heart attack. Alan was struck hard and deep.

Alan Helmick: I think that he died that day-- a big part of him. You know, he lost my mother who he'd been with since he was 14, his love, his life. I'm sure that everything that he thought was real was ripped out from under him.

Months passed before Alan picked himself up, and decided to get out on his own. He realized he still had some unused credit at a ballroom dance studio he had once taken classes at.

Alan Helmick: He thought, "Well, maybe it's something I should do." He's trying break out of-- you know, the-- the slump he's in, so he goes back to the classes.

And that's where he met his dance instructor -- 48-year-old Miriam Giles. Miriam had lived in Florida, and recently moved to Colorado to start a new life of her own.

Like Alan, she was still raw from tragic loss -- her daughter, Amy, had passed away in 2000 from a drug overdose, and her husband, Jack, had committed suicide two years later.

Romance was the last thing on Miriam's mind, but as her friend Penny remembers it, Alan was persistent.

Penny: He went for dance lessons. She wasn't interested in anything else. He was. She told him no. He had to fight to get her to go out with him.

DennisMurphy: What do you think he found in her, in that kind of mysterious chemistry of people becoming couples?

Penny: She was exhilarating. She was very lively. And she'd match him in his joy of doing the things they liked to do. And you get someone to do it with. You can't beat that.

The couple soon became inseparable -- Miriam moved into Alan's home in Delta. In June 2006, they decided to marry.

DennisMurphy: Did you see the lights go back on in your father?

Alan Helmick: He was definitely – miles, miles better. Yeah, I think that the traditional role that he grew up in -- you know, there's the man and the woman. And they grow old together and they die together. So I think that she filled a purpose that he needed sorely.

The Alan everyone had missed -- fun-loving, happy, and optimistic -- was finally back. And with his new wife, he was looking for new business opportunities too.

Before his wedding, Alan stopped by the office of his accountant and longtime friend, Bob Cucchetti.

Bob Cucchetti: Alan came in, and we were doing some taxes. And he was-- he said that he was gonna invest in-- a dance salon. And-- and--

DennisMurphy: Where did that itch to open a dance studio come from, do you think?

Bob Cucchetti: Oh, it had to be Miriam. I mean, hell, why would he do that? I mean, like having a root canal.

Well, if Alan wanted to open a dance studio, so be it. Supportive friends of many years, people like Ed Benson, a contractor, signed up for dance lessons along with his wife.

EdBenson: Alan actually put on an exhibition. Alan and Miriam danced. And-- Alan is a very competitive person and-- he was good. I mean, whoa, he was very, very good.

But a small-town ballroom dance studio would always be a business of the heart, and a couple years later, it was bleeding money. By then, though, Alan and Miriam had turned their attentions in a new direction.

They had bought a 40-acre property in Whitewater, a rural community just outside Grand Junction, with the idea of starting a horse-breeding business. Alan's accountant didn't sugar-coat his opinion of the venture.

Bob: That was a nightmare. I tell him, I said, "Alan, anybody who gets-- raisin' horses is gonna lose some money." But-- he was determined he was gonna make money at it.

Friends thought it a little unusual that someone as smart and business-savvy as Alan would get involved in such a risky start-up. But they just chalked it up to an expensive hobby.

EdBenson: It was just, you know, just something to make his wife happy. I-- I don't think he was, you know, naive enough to realize that he was gonna make money doing that.

Whatever the case, the Helmicks seemed to love the challenge. And for two people who had lost so much in their lives, this seemed like a new adventure... One they'd share together. It might have all ended happily there, but it didn't.

On June 10, 2008, the local news carried the story of an apparent robbery-homicide out in the Helmicks' neighborhood.

EdBenson: My wife and I were starting to get ready for bed, and I-- I said, "I wonder if that's Alan?" And by the-- morning's news release, it was out that that is exactly who it was.

Alan Helmick had been murdered in his home, the victim apparently of a robbery gone bad. But as investigators got to work, they would come up with the theory of a crime more shocking, and darker than anyone on the western slope of the Rockies could have guessed.

Just before noon on June 10, 2008, Miriam Helmick found her husband shot to death in their rural Colorado home. She called 911 saying it looked as though it had been a robbery. When the Mesa County investigators arrived, Miriam was still kneeling over her husband's body. Alan had been shot in the head.

Lying next to him: a .25-caliber shell casing, a wallet, and a cell phone.

Kieran Wilson: It was a very big story. This is a small town. And people don't just get murdered randomly here.

Kieran Wilson, then a reporter for NBC'S Grand Junction affiliate, KKCO-TV, was sent out to cover the story that day. It became clear to her that investigators weren't treating this as a simple robbery-gone-bad. The crime scene appeared off.

Kieran Wilson: I guess some drawers had been opened. Things were in a sort of disarray.

DennisMurphy: So some evidence that the house had been ransacked a little bit?

Kieran Wilson: Possibly. I know they were looking into it as a staged robbery homicide.

Staged? Who would want to stage a crime scene? As a matter of routine, detectives would look first at the spouse. But when they tested Miriam's hands for gun shot residue, they found nothing. And it was clear that Miriam had been nowhere near her home that morning.

Amy Hamilton is a reporter for the Grand Junction Daily Sentinel.

Amy Hamilton: Alan had given her money to go shopping, so she left very early in the morning. And they were gonna meet for lunch after she had done some shopping. So as she is going around town to different stores she's calling Alan and saying, "I'm here now. You should pick up your phone maybe."

Based on receipts and surveillance video, investigators were able to track Miriam's movements that morning -- from an 8:49 a.m. stop at a convenience store to four other locations, before ending up here at a Chinese restaurant at 11:00, where she'd planned to meet Alan for lunch.

Amy Hamilton: He didn't show up while she was waiting in her car. And so she called him again and she said, you know, "Where are you? Are you standing me up?" And-- so then when she didn't see him, she decided to drive back to her house.

That's when she discovered her husband, lying dead on the kitchen floor.

Who had visited Alan while Miriam was out? Was it a stranger out to get him -- some shady business deal gone bad?

Ed: Everyone of course had a theory of what had happened. And, but as far as a break-in robbery thing, no. That -- that wasn't plausible.

And the theories about Alan's death became more complex after authorities in a nearby town revealed that Helmick had been the target of an apparent murder attempt just weeks before he was found shot to death.

Forty-one days before Alan's murder, he was involved in a disturbing incident in his hometown of Delta. It happened right here, outside the office of his title company. Alan had just finished a business meeting -- he was selling his company -- sitting in his car, waiting for Miriam to come back from the ladies’ room. All of a sudden, the gas tank on his Buick caught fire. The police thought it was a case of arson.

With the press now ramping up coverage of the case, Miriam Helmick decided to sit down with local television reporters, and address rumors about that arson investigation.

Miriam Helmick: I don't know what the Delta Police have come up with since then. They never would call us back when he called, so.

Question: Think at all that they might be connected?

Miriam Helmick: Good possibility. I was letting them figure that out. We, um, it was uh, definitely a, I want to say an interesting day because that was the first time, I mean, it was a shock to us, you know. But he never mentioned anything about anybody that could, would do something like that.

In the days after Alan's murder, amidst the grief and confusion, Miriam had to confront one more emotion -- fear. Because it seemed her life might also have been in danger.

Back at home, Miriam reported some odd things happening around her - doors unlocked, lights turned on, cabinet drawers that were pulled open. She asked the neighbors if anyone had seen a strange car in the area, but no one had. But perhaps the most troubling sign of all was left right there on her doorstep - and what could that be but a warning that her nightmare was far from over.

Penny Lyons: It was about ten days after the funeral. Miriam had been saying for about three days that odd things were going on in the home.

Dennis Murphy: She thought what? Someone was coming in the house and trying to spook her?

On Thursday, June 26, Penny Lyons offered to accompany her friend, Miriam, home. As they pulled into the garage that evening, Miriam noticed that police tape -- which she had purposely left on her front door -- had been removed.

Penny Lyons: So we walked over to the front door. And down underneath the welcome mat was a bright canary yellow envelope. So I picked it up. And handwritten on the front said, "To the grieving widow." So we took the card out. And it had a cartoon on the front with the Einstein quote. When we opened up the card, handwritten inside it said, "Alan was first. You're next. Run, run run."

It had been two weeks since her husband had been found dead in their home, and Miriam Helmick was telling friends she was convinced someone was out to get her too. Imagine how she felt when she found a greeting card like this, with a message inside that read, "Alan was first, you're next. Run, run, run."

Penny Lyons was with her when she discovered that greeting card.

Penny Lyons: She just started to shake and go down. I mean, how can you not? Alan had been murdered and now there's a physical threat that you're looking at. Good God, scare the living daylights right out of you. So I just told her to, "Get in the car, get in the car, get in the car." And I had enough sense I guess to grab the card and envelope, throw it in the back seat so I could at least throw it in an envelope.

Investigators started to trace that greeting card -- tracking down all the local stores where it could have been sold.

Could the card have come from a shady associate who'd been out to get Alan, and who was now out to get Miriam too? Just where was this case heading?

In the absence of hard information rumors began to fill the void -- word on the street was it might have had something to do with a business deal gone bad.

Bob Cucchetti, Alan's accountant, heard the scuttlebutt.

Bob Cucchetti: There was some talk about-- him-- owing people money. And you know what, that's a bunch a crap. Nobody owes-- nobody around here does that. He had a couple of debts. But-- no.

The other rumors, though, were about Miriam herself. Increasingly, in the court of public opinion, as well as in the official investigation, it was felt Miriam had to start explaining herself better.

Investigators had been digging into her story -- and found that, once you broke down her alibi, the grieving widow -- so graceful on the dance floor -- was looking more and more like a suspect.

Yes, she had spent the morning running errands -- that much was well-documented. But there was a mismatched account of how Miriam had cleared the deck for that busy day's schedule.

Originally, Alan's granddaughter was expected at the house for an afternoon horse-riding lesson. But early that morning, Miriam phoned the riding instructor, Sue Boulware, to cancel.

SueBoulware: The granddaughter lives about 45 minutes from their house, and they hadn't gone and picked her up the night before, which is what they usually did.

That was the story Miriam told the riding instructor. But she gave a different version of why the lesson had been cancelled when she talked to Alan's daughter, Portia. Miriam told her it was the riding instructor who'd cancelled. The instructor says that's not true.

SueBoulware: Miriam cancelled the riding lesson.

And Miriam had a bogus explanation for why Alan's daughter had been unable to reach him on the phone the night before:

Kieran Wilson: Miriam had said that he came home from the Elks Lodge in Delta, and that he was very drunk and she had to put him to bed.

Investigators checked out that story, talked to the bartender at the elks lodge and learned that Alan hadn't been in that night at all.

And then there was this -- when investigators ran a test for gun shot residue on Miriam's car, they found a curious particle on her steering wheel. By now, Alan's children were starting to get suspicious.

AlanHelmick: There's so many odd things that happened concerning that woman that in retrospect-- in-- in hindsight that I look back and say, "That just doesn't seem right."

All along, they'd been worried for their father -- no more so than after his marriage to Miriam when his physical condition began to slide downhill fast.

AlanHelmick: He was sick a lot during that time, now, which was very odd.

Dennis Murphy: Fluey kind of thing?

AlanHelmick: Yeah. He's in "I'm in bed." You know.

Dennis Murphy: Was that like him to be sick or complain about being sick?

AlanHelmick: No. Never. Never. Strong as an ox.

When crime scene investigators examined the Helmick home, and looked in the medicine cabinet, they found that Alan had been anything but the picture of health.

Kieran Wilson: I think at one point they found that Alan had been on nine different medications. That's a lot for one person.

It wasn't just the number of prescriptions that was disturbing. When technicians examined the computer from Miriam's desk, they found some alarming searches done in the weeks before Alan turned up dead -- searches on drugs found in the Helmick house. A search on phrases like "overdose Viagra," "Ambien death," and "Lisinopril death."

Kieran Wilson: Things about how to put a horse down. Specific searches about Ambien overdoses, Viagra overdoses, what might happen if you mixed those two drugs.

Alan's children told investigators they suspected Miriam of poisoning their father. But when the medical examiner conducted the autopsy, they found no trace of poison in the body. The doctor did discover that Alan had suffered from serious heart disease. One of the symptoms of that disease is extreme fatigue. Friends, though, still wonder if Alan had been laced with something hard to detect.

Bob: He was seriously bedridden. You know, I mean, he was frail, yeah. I think he was poisoned.

Whatever the reason for Alan's illness, one thing was clear -- bedridden almost constantly, he had been virtually unreachable in the weeks before his death. Whenever someone called his cell phone, it was more than likely that Miriam would pick up.

AlanHelmick: Yeah. And that was – okay, there you go, that was one of the weird things. She started answering his cell phone. Which was strange and I thought she had her own phone, you know, the house phone was understandable. But the cell phone he would answer that, always had, same number for years. All of a sudden she's answering every cell phone call.

And in the days immediately before Alan's death, whenever his daughters would phone, their calls went straight to voicemail and were never returned. That wasn't like their father. One daughter later told investigators she saw it as "isolation through manipulation."

AlanHelmick: We did not know at the time exactly what happened, although we all had of course our feelings, but um --

Dennis Murphy: You and all your sisters?

AlanHelmick: Yeah. Amazingly so. When we got together, we all saw eye to eye, which was kind of odd. We all kind of looked at each other and went, "Really you felt that way too?"

His family weren't the only one having trouble getting through. For the last three months, Alan's bank had also been trying to get ahold of him, with some urgent news concerning his finances... News that Miriam definitely did not want him to hear.

It had been two weeks since her husband had been found dead in their home, and Miriam Helmick was telling friends she was convinced someone was out to get her too. Imagine how she felt when she found a greeting card like this, with a message inside that read, "alan was first, you're next. Run, run, run."

Penny Lyons was with her when she discovered that greeting card.

PennyLyons: She just started to shake and go down. I mean, how can you not? Alan had been murdered and now there's a physical threat that you're looking at. Good God, scare the living daylights right out of you. So I just told her to, "Get in the car, get in the car, get in the car." And I had enough sense I guess to grab the card and envelope, throw it in the back seat so I could at least throw it in an envelope.

Investigators started to trace that greeting card -- tracking down all the local stores where it could have been sold. Could the card have come from a shady associate who'd been out to get Alan, and who was now out to get Miriam too? Just where was this case heading?

In the absence of hard information, rumors began to fill the void. Word on the street was it might have had something to do with a business deal gone bad.

Bob Cucchetti, Alan's accountant, heard the scuttlebutt.

BobCucchetti: There was some talk about him owing people money. And you know what, that's a bunch a crap. Nobody owes-- nobody around here does that. He had a couple of debts. But-- no.

The other rumors, though, were about Miriam herself. Increasingly, in the court of public opinion, as well as in the official investigation, it was felt Miriam had to start explaining herself better.

Investigators had been digging into her story, and found that, once you broke down her alibi, the grieving widow -- so graceful on the dance floor -- was looking more and more like a suspect.

Yes, she had spent the morning running errands -- that much was well-documented. But there was a mismatched account of how Miriam had cleared the deck for that busy day's schedule.

Originally, Alan's granddaughter was expected at the house for an afternoon horse-riding lesson. But early that morning, Miriam phoned the riding instructor, Sue Boulware, to cancel.

Sue Boulware: The granddaughter lives about 45 minutes from their house, and they hadn't gone and picked her up the night before, which is what they usually did.

That was the story Miriam told the riding instructor. But she gave a different version of why the lesson had been cancelled when she talked to Alan's daughter, Portia. Miriam told her it was the riding instructor who'd cancelled. The instructor says that's not true.

Sue Boulware: Miriam cancelled the riding lesson.

And Miriam had a bogus explanation for why Alan's daughter had been unable to reach him on the phone the night before:

Kieran Wilson: Miriam had said that he came home from the Elks Lodge in Delta, and that he was very drunk and she had to put him to bed.

Investigators checked out that story, talked to the bartender at the Elks Lodge and learned that Alan hadn't been in that night at all. Why was Miriam making stories up? By now, Alan's children, who had never entirely warmed to their new stepmother, were starting to get suspicious.

AlanHelmick: There's so many odd things that happened concerning that woman that-- in retrospect, in-- in hindsight that I look back and say, "That just doesn't seem right."

All along, they'd been worried for their father -- no more so than after his marriage to Miriam when his physical condition began to slide downhill fast.

AlanHelmick: He was sick a lot during that time, now, which was very odd.

Dennis Murphy: Fluey kind of thing?

AlanHelmick: Yeah. He's in "I'm in bed." You know.

Dennis Murphy: Was that like him to be sick or complain about being sick?

AlanHelmick: No. Never. Never. Strong as an ox.

When crime scene investigators examined the Helmick home, and looked in the medicine cabinet, they found that Alan had been anything but the picture of health.

Kieran Wilson: I think at one point they found that Alan had been on nine different medications. That's a lot for one person.

It wasn't just the number of prescriptions that was disturbing. When technicians examined the computer from Miriam's desk, they found some alarming searches done in the weeks before Alan turned up dead -- searches on drugs found in the Helmick house.

Kieran Wilson: Things about how to put a horse down. Specific searches about Ambien overdoses, Viagra overdoses, what might happen if you mixed those two drugs.

Alan's children told investigators they suspected Miriam of poisoning their father. But when the medical examiner conducted the autopsy, they found no trace of poison in the body. The doctor did discover that Alan had suffered from serious heart disease. One of the symptoms of that disease is extreme fatigue. Friends, though, still wonder if Alan had been laced with something hard to detect.

Bob: He was seriously bedridden. You know, I mean, he was frail, yeah. I think he was poisoned.

Whatever the reason for Alan's illness, one thing was clear -- bedridden almost constantly, he had been virtually unreachable in the weeks before his death. Whenever someone called his cell phone, it was more than likely that Miriam would pick up.

Alan Helmick: None of our calls got returned.

DennisMurphy: Calling both the house phone and his cell phone?

Alan Helmick: Yeah. And that was -- okay there you go, that was one of the weird things. She started answering his cell phone. Which was strange and I thought she had her own phone, you know, the house phone was understandable. But the cell phone he would answer that, always had, same number for years. All of a sudden she's answering every cell phone call.

And in the days immediately before Alan's death, whenever his daughters would phone, their calls went straight to voicemail and were never returned. That wasn't like their father. One daughter later told investigators she saw it as "isolation through manipulation."

Alan Helmick: We did not know at the time exactly what happened, although we all had of course our feelings, but, um --

DennisMurphy: You and all your sisters?

Alan Helmick: Yeah. Amazingly so. When we got together, we all saw eye to eye, which was kind of odd. We all kind of looked at each other and went, "Really you felt that way too?"

His family weren't the only one having trouble getting through. For the last three months, Alan's bank had also been trying to get a hold of him, with some urgent news concerning his finances... News that Miriam definitely did not want him to hear.

In the weeks after Alan Helmick had been murdered in his home, authorities were regarding his widow, Miriam, as their main suspect. But even with evidence piling up against her, some friends like Penny Lyons were convinced she was innocent. She couldn't conceive of a motive.

Penny Lyons: He took care of everything. Her whole life was Alan and everything provided in that life was provided by Alan, so what -- what -- there's nothing to gain.

Dennis Murphy: You want a little dance studio? I'll buy you one.

Penny Lyons: Yeah, you want to do horses --

Dennis Murphy: You like the horses --

Penny Lyons: -- we'll do the horses.

Dennis Murphy: We'll have a horse farm.

Penny Lyons: Yeah, it was awesome. All that mattered was that you do what you enjoy.

If Miriam had murdered her husband, she certainly didn't seem to benefit in the immediate aftermath. Alan had made sure to keep all their bank accounts and credit cards under his name only. The Helmicks’ horse-trainer, Sue Boulware, said Miriam had been cut out of her husband's finances by design.

Sue Boulware: Miriam told me, after this all happened, that she wasn't on any of the bank accounts because the family -- Alan's family -- were worried that she was a younger woman, and that she might want his money. And to make the family happy, they had signed a pre-nup.

In fact, in the days and weeks after Alan's death, without Alan handing her cash as he always had, miriam had to borrow from friends just to buy groceries and gas. And she was struggling to pay off her bills.

Sue had to help Miriam sell her horses just so she could get paid.

Sue Boulware: I needed to be paid for my services, as the bank had put a hold on all the funds for any checks that had been written.

Even on the most cynical of ledgers, it seemed that always-so-generous Alan was worth more to Miriam alive than dead. In that TV interview, she acknowledged that her husband had been like a sugar daddy to her.

Miriam Helmick: His favorite saying was have fun like hell, so anytime he knew I was going shopping or gave me money or anything he'd say, "Have fun like hell."

But was Miriam getting more from Alan than simply walk-around pocket money? It appeared she had been and it also seemed that Alan didn't know about the extra allowance that she was giving herself, if that's what it was.

Investigators discovered that for the last year Miriam had been forging checks in Alan's name. Detectives found at least seven checks totaling more than $16,000 that had been written payable to herself and the dance studio.

Allan Laurel had been hired to manage the dance studio, and he says he suspected all along that Miriam had been signing Alan's checks.

Allan Laurel: I usually figured that Alan Helmick was just perfectly okay with Miriam handling the checks in and out of the studio.

Dennis Murphy: You knew they were legitimate bills? The money that was owed for the month, the fees to the instructors.

Allan Laurel: Sure. Legitimate bills were getting paid.

Of course, it's not uncommon for husbands and wives to sign each other's checks -- maybe he knew about it. But investigators spoke to the manager at Alan's bank and found something else Miriam may have been trying to hide from her husband.

In the three months before Alan died, the bank had been trying to contact him, but could never get past his voicemail. They even buttonholed Miriam once when she'd visited the bank, and told her Alan really did need to call them immediately. He never did. So finally, his bankers resorted to writing letters.

Here at the Helmick house, the investigators found a letter waiting in the mailbox. It was posted four days before Alan's murder. And if he'd lived to take delivery of that letter, he would have learned that he was in serious financial trouble. It was a notification from the bank telling him that almost $140,000 had been transferred from his personal checking account to cover two outstanding commercial loans - and the bank wanted him to pay off the balance on those loans immediately. Did Alan realize he was short of cash and was that why he was dodging his bankers?

His accountant -- who regarded Alan as a friend and an honorable businessman -- said it would have been totally out of character for Alan to have been evasive if he owed anyone substantial money.

Bob: He was a banker. I mean, he, you know, if he couldn't pay a bill, he would sure go down and explain to the guy and make arrangements on it.

When investigators looked at what appeared to be monkey business going on in Alan's financial affairs... and when they considered Miriam's apparent lies about how it was that she was free that morning to run so many errands, it became harder and harder for them to eliminate her as a suspect.

Dennis Murphy: When you hear the whole mosaic of Miriam's story, you wonder what is going on.

Kieran: There's what seems to be so much evidence against her. It's hard to look the other way.

Alan: I was already 110 percent convinced in my mind that -- if she didn't do it that she was solely responsible for who did.

The business about the checking accounts was intriguing but also perhaps ambiguous as evidence. What happened next, though, would be the investigative breakthrough the detectives had been hoping for.

And it had to do with that greeting card left on Miriam's doorstep -- the one that threatened she might be the killer's next victim. What a surprise that turned out to be.

In July 2008, one month after Alan Helmick had been shot dead in his home -- investigators had a major breakthrough in their case. It had to do with that mysterious greeting card that had been left for Alan's widow, Miriam, at the end of June. "Alan was first, you're next." The message inside read, "Run, run, run."

Penny Lyons was with Miriam when she found the card.

Dennis Murphy: You're asked some more questions about that card that was found. And there's a very disturbing story that comes to light, huh?

Penny Lyons: Yeah.

The disturbing story goes like this: Investigators found that this particular card was sold at a chain of "city market" grocery stores. Using the UPC code on the back of the card, city market was able to trace the card to three purchases from the latter half of June. They had surveillance video of those purchases. And of those three buyers, investigators recognized one in particular.

Penny Lyons: According to the videotape, Miriam bought the card at the City Market that's right next to my home.

Miriam herself had bought the card on June 22nd, four days before she'd "discovered" it with Penny.

DennisMurphy: If that's all true, the business about the card, Penny, it looks as though she was using you --

Penny Lyons: Yeah, it does.

DennisMurphy: As the kind of witness to this set-up story about a intruder continuing to harass her.

Penny Lyons: If that's true, yeah.

DennisMurphy: What do you do with that information? That's got to be just awful to deal with.

Penny Lyons: No, it's not. It's really not. My feelings aren't an issue here. All I was doing was being the best friend that I could. Now however someone chooses to use that, that's out of my control. And all that matters now is finding the truth.

The truth about Miriam would be hard for friends to hear. As investigators continued to dig into the story of the widow, they found some disturbing anecdotes from her past.

Right before moving to Grand Junction, Miriam had gotten a job in Gulfport, Miss., as a dance instructor at a studio there.

In 2004 it got messy. Her boss at the dance studio accused her of petty theft and embezzlement. She was eventually found not guilty on those charges. But earlier that year, Miriam had gotten in real trouble with the law. Back in Jacksonville, Fla., she'd tried to cash almost $7,000-worth of counterfeit checks. She admitted the crime, and spent three days in jail - news to her step-son.

Alan: See, we didn't know anything about those things. Those-- those weren't things that were presented. That was not (chuckle) in the wedding invitation, you know.

Alan's son may have been in the dark, but some of Alan's friends, at least, had an inkling of Miriam's past.

Ed: She told us, there was allegations of embezzlement. And she really didn't deny it. It kinda made you wonder. Matter of fact, at some point, my wife and I both says, "Boy, I wonder if Alan really knows what he's gotten himself into here."

DennisMurphy: Were people saying things like she's getting her mitts into him?

Bob: Yes.

DennisMurphy: She's a gold digger.

Bob: Yes.

DennisMurphy: She wants to get Alan wrapped up.

Bob: Yep. And they said that Alan'd give her whatever she wanted.

Still, friends had hoped for the best. And they were, after all, fond of Miriam - until that day in June when Alan turned up dead.

Ed: I feel that Miriam is either responsible for Alan's death and or he -- it was because of something that she did or directed.

And it became even more difficult to regard Miriam as simply misunderstood when new information was revealed about that ominous and wacky apparent attempt on Alan's life by someone torching his car's gas tank that day weeks before his murder. Miriam had been asked what was up with that in her TV interview:

The Delta police department turned over its report on the bizarre incident and it looked as though Alan did know his attacker that day, knew her all too well.

According to the police, a home-made wick had been dunked in the gas tank of the Buick. Miriam, who'd been fiddling around in the trunk just moments before going to the ladies' room, had been the only person near that gas tank.

Kieran: Apparently, she was fumbling around, had dropped her purse -- was looking for her cigarettes and things like that. And then she went inside. And Alan smelled smoke, or saw smoke. At that point, obviously he got out of the car.

Alan was able to snuff the fire easily enough. But he wasn't able to douse the anxiety raised by the police officers when they told him what they'd found.

Kieran: They told him they had surveillance footage from a business that was across the street. And they said, they -- they have the person on there that had tried to set the car on fire. "What if we told you Miriam was that person?" Alan said, "No, I don't think she would do that. But I could be wrong."

Dennis Murphy: Wasn't saying, "That's a crazy idea,"

Kieran: He was saying, "That's crazy. Wait, maybe it could happen."

Dennis Murphy: In fact, they didn't have a security camera picture?

Kieran: No, they didn't have anything of the sort.

Dennis Murphy: They were just squeezing him to see what he would say on the hypothetical.

By August, Miriam -- now out of cash and with dwindling support in town -- had left Colorado and returned to Florida to live with her son.

Penny: I was actually very glad that she was there with him. That was where she would have the most support. And the officers had never said she couldn't leave. So there was no reason why she couldn't go.

Investigators, though, were keeping tabs on her. By the end of the year, they were ready to make their move. On Dec. 8, the Mesa County Sheriff's office asked authorities in Florida to assist in an arrest. The deputies kept Miriam under surveillance, before pulling her over on this busy street.

Authorities, though, were keeping tabs on her.

On december 8, they arrested her in Jacksonville. At that time, they found some strange items in her purse -- a driver's license, paycheck stubs, and credit cards -- all under the name of Sharon Helmick. Miriam, it appeared had tried to assume the identity of alan's first wife.

Judge: Is that right ma’am, you want to go back to the Rocky Mountain State to take care of this? Alright, set.

Miriam was transferred back to Colorado, where ten days later, she was charged with first-degree murder, attempted murder, and forgery. Mesa County Sheriff Stan Hilkey:

Stan Hilkey: She was not a person that could be eliminated from the very beginning. Pretty confident that we've got the person responsible.

As the news of her arrest began to spread across two states, more questions began to emerge about her past, including questions about her first husband, whose death had long been ruled a suicide. Now, people were asking, could it have been something else?

In December, Miriam Helmick was charged in Colorado with forgery, attempted murder, and murder in the shooting death of her husband, Alan. The case is now in the hands of the Mesa County district attorney's office. While prosecutors in Colorado are busy building their case, authorities in Florida are fielding fresh inquiries about Miriam's past there.

She had been arrested in Jacksonville where she was staying with her son. Her Florida history dates back to when she was known as Miriam Giles.

Kieran: She had lived in Jacksonville, Florida, for a very long time. And she had a daughter, a son, and a husband. And her husband we actually found out through the course of our investigation had shot himself in his head while they were laying in bed together.

Dennis Murphy: Together in bed? And he's a suicide?

Kieran: They ruled it as suicide. They tested her hands for gun powder residue. They said, "This case is closed. Ruled suicide. We'll bring it back up if we find anything suspicious."

Was it "suspicious" that six years later, Miriam's second husband is also found dead at home from a gunshot wound to his head? Someone asking that question today is Tim Giles, the brother of Miriam's first husband, Jack.

Tim Giles: I mean, after Jack's suicide Miriam was very quick to-- to go out and do her own thing. She was really almost too quick.

Tim lost touch with his sister-in-law after jack passed away in 2002. In fact, he had no idea what had happened to Miriam -- or that she'd been charged with murder -- until we called him out of the blue.

Tim Giles: It shocked me a lot -- a lot.

Dennis Murphy: Probably hadn't thought of the name Miriam in a while?

Tim Giles: I had to open that door in my mind and finally figured who Miriam was again. And Miriam Helmick didn't register at all. Because I never knew she was remarried. I never knew where she was. But once I sat down, and started thinking about it, and started to think about the circumstances of Miriam with Jack, my brother, it didn't surprise me.

It didn't surprise him, because all along Tim had suspected that Miriam had been involved in Jack's death. He never bought Miriam's story -- that jack had been so overwhelmed by grief following their daughter's death that he committed suicide.

Tim Giles: Jack just wasn't that depressed. Jack was a workaholic. Jack was just not that type of person that would just wanna shoot himself in the head for -- because he's depressed over Amy who passed away two years before that.

And, according to Tim, Jack and Miriam had far from the perfect marriage. They'd even separated at one point -- when Miriam left jack to live with another man. When she returned, he thought, things were never quite the same.

Tim Giles: They always seemed indifferent. If Miriam was in the kitchen Jack was in the front room. If Miriam's in the front room. Jack was in the kitchen.

Dennis Murphy: That says something. Huh?

Tim Giles: Yeah. They were never really together. My personal feeling, is that they just tolerated each other because of the kids.

And there was something else that was strange -- something Tim didn't know -- and we didn't discover, until we interviewed him. When we went through the original sheriff's report, we saw that Jack had been shot on the right side of his head, and that the gun was found in his right hand.

The Jacksonville Sheriff's Office says it was aware all along that jack was left-handed, and issued this statement: "The Giles case was revisited back in June once we learned of the death investigation of her husband. We did not discover anything new or anything that would merit reinvestigating of our case... At this time, our case remains a closed suicide incident."

Back in Colorado, another family is also waiting for answers.

Alan: I've spent a lot of time staring at the wall and wondering what it is as a son I could have done -- maybe you know, be more communicative about my feelings about this woman.

Miriam, who has yet to enter a plea on the charges against her, is in a Colorado jail, awaiting trial for the murder of Alan Helmick. Until that court date, unanswered questions hover over the case.

Questions like: the timeline, when that day was he killed. And if Miriam is his killer, why did she do it if pre-nups ruled her out as an heir? Alan's friend Ed Benson, for one, has a theory about a motive -- maybe Alan had finally realized that Miriam had sticky fingers... And he'd had enough of it.

Ed: My thoughts on something like that were maybe he finally had discovered that there was a lot of money missing. And that you know, that final awful moment of realization that your, your mate has -- is stealing from you. Maybe that pushed her over the edge.

But other friends, like Penny Lyons, are at a loss. Nothing about the crime makes sense.

Penny Lyons: You know, for me, if she did do this, then I just didn't lose one friend. I lost two that summer. Because the friend that I had could never have done this.

Dennis Murphy: The Miriam you knew.

Penny Lyons: Yeah.

Dennis Murphy: Who made Alan very happy and vice versa.

Penny Lyons: Yeah, very much so.

However the questions are finally resolved, it won't change the sad trajectory of Alan Helmick's life -- that a man so beloved, so generous, and so full of life -- should come to an end like this.

Dennis Murphy: You can't get in the time machine and throw your dad in the truck and go fishin'-- take him away from all that?

Alan: You know, that's something I've been robbed of. The ability to exceed my father's expectations. To be-- you know, that older guy where we're sitting down and he says, you know, "You did good here." I'll never get that. I've been robbed of that completely.

Dateline wires the home of a volunteer, Jenny, from top to bottom with hidden cameras. Then she called repairmen to her house for a simple problem we created as a test with Jenny's pool. NBC's Chris Hansen reports.